Configuring an optical network termination

ABSTRACT

A method for performing ONU Management and Control Interface (OMCI) synchronization includes receiving an OMCI message containing a OLT-G entity identifying OLT&#39;s vendor identification (ID) and version. The method also includes determining if an OLT vendor identification (ID) matches with a current vendor ID and if an Optical Line Terminal (OLT) version is compatible with current OMCI handlers. When the OLT vendor ID fails to match with the current vendor ID, automatically performing a OMCI handler switching process. The OMCI handler switching process includes setting a current OLT vendor as a new OLT vendor ID, deleting a OMCI configuration previously stored in the flash memory after setting the new OLT vendor ID, and rebooting the ONT to allow the ONT to initialize a OMCI configuration using a new OMCI profile.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of, and claims priority to,U.S. application Ser. No. 17/068,751, filed on Oct. 12, 2020. Thisapplication incorporates the entirety of the subject matter recited inthe above-identified application.

FIELD

The present invention relates to an optical network termination (ONT),and more particularly, to configuring the ONT.

BACKGROUND

In telecommunication, an eye diagram is an oscilloscope display in whicha digital signal from a receiver is repetitively sampled and applied tothe vertical input, while the data rate is used to trigger thehorizontal sweep. See, for example, FIG. 1, which is related artillustrating an eye diagram 100. An eye diagram 100 is a pattern lookslike a series of eyes between a pair of rails, and is a tool forevaluating the combined effects of channel noise and inter-symbolinterference on the performance of a baseband pulse-transmission system.Further, eye diagram 100 is a synchronized superposition of all possiblerealizations of the signal of interest viewed within a particularsignaling interval.

In an eye diagram, the eye crossing percentage is a measure of anamplitude of crossing points relative to One level and Zero level. SeeEquation (1) below.

$\begin{matrix}{{{Crossing}\mspace{14mu}{percentage}} = {\frac{{{Crossing}\mspace{14mu}{level}} - {{Zero}\mspace{14mu}{level}}}{{{One}\mspace{11mu}{level}} - {{Zero}\mspace{14mu}{level}}} \times 100\%}} & {{Equation}\mspace{14mu}(1)}\end{matrix}$

Crossing point is an indirect measurement of the quality of the eyediagram, and indicates the timing occurrence of One level and Zerolevel. FIG. 2 is an image 200 illustrating a classic sample how the timeof Signal One and Signal Zero impacts the crossing point. For example,image 200 indicates that the crossing point is changed by changing thetiming of Signal One and/or that of Signal Zero. In fact, the crossingpoint is not a parameter that the transceiver can be calibrateddirectly. It always has to be indirectly impacted by other parameterssuch as the timing of signals.

In International Telecommunication Union (ITU-T) G.984.2 and itsamendment, the crossing percentage of a gigabit-capable passive opticalnetwork (GPON) signal eye diagram is never defined as a changeableparameter. FIG. 3, for example, is a diagram 300 illustrating a mast ofthe eye diagram for the upstream transmission signal. The nominal valueof the crossing percentage is marked as 0.5 (or 50%). This implies thatthe Signal One and Signal Zero shall take equal time. This is also theassumption for many other optical parameters such as the sensitivity,signal penalty, the BER, etc.

Let's take the ONT discussed in U.S. Pat. No. 10,560,190 B2 (the “'190patent”). In the '190 patent, the crossing point must be calibrated to40%. Further, the '190 patent suggests that the transceiver has toshorten the timing of Signal One and/or extend the timing of SignalZero. To keep the transmission rate of the GPON signal, the '190 patentdiscussing making the wave of Signal One narrower.

This, however, makes the Signal One harder to be detected, or in somecases, may be mistakenly detected as Signal Zero. This change alsoresults in the changes to the sensitivity and the bit error rate (BER)of the transceivers, which are difficult to compensate. Furthermore, thelower crossing percentage results in longer time at lower level ofoptical power and cause challenges to recover the signal frequencywhich, in some worst cases, causes the loss of synchronization andpotential transmitted bit missing.

Thus, when calibrating ONT's, the following challenges are presented—(1)the crossing point cannot be calibrated directly and (2) the signalquality is reduced, causing additional transmission challenges. Forexample, this may result in higher BER, lower signal sensitivity, andreduced coverage range.

Thus, an alternative approach other than the use of crossing points maybe more beneficial.

Some conventional methods, such as those discussed in the '190 patent,use delimeter bytes when configuring an ONT. However, knowing thatdelimiter bytes are 24-bit data and are contained in 3 bytes (e.g.,Octet 7 to 9) and knowing that a central processing unit (CPU) processesthe data of 8-bit, 16-bit, 32-bit, or 64-bit, the data within thedelimiter bytes has to be converted to multiple parts of a certainlength in order for the data to be processed.

Thus, an alternative approach that uses octet 10, which is 8-bit, may bemore beneficial.

SUMMARY

Certain embodiments of the present invention may provide solutions tothe problems and needs in the art that have not yet been fullyidentified, appreciated, or solved by current ONT technologies. Forexample, some embodiments of the present invention pertain toconfiguring the ONT.

In an embodiment, a process for configuring an optical networktermination (ONT) includes receiving an upstream overhead physical layeroperation administration and maintenance (PLOAM) message from an opticalline terminal (OLT). The process also includes extracting byte 10 datafrom the upstream overhead PLOAM message to identify a transceiver typeof the OLT, and matching the transceiver type of the OLT with one of aplurality of sets of optical parameters. The process further includesstoring the matched transceiver type of the OLT in a double date rate(DDR) memory prior to completing a ranging process with the OLT.

In another embodiment, a method for performing ONU Management andControl Interface (OMCI) synchronization includes receiving an OMCImessage containing a OLT-G entity identifying OLT's vendoridentification (ID) and version. The method also includes determining ifan OLT vendor identification (ID) matches with a current vendor ID andif an Optical Line Terminal (OLT) version is compatible with currentOMCI handlers. When the OLT vendor ID fails to match with the currentvendor ID, automatically performing a OMCI handler switching process.The OMCI handler switching process includes setting a current OLT vendoras a new OLT vendor ID, deleting a OMCI configuration previously storedin the flash memory after setting the new OLT vendor ID, and rebootingthe ONT to allow the ONT to initialize a OMCI configuration using a newOMCI profile.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of certain embodiments of the inventionwill be readily understood, a more particular description of theinvention briefly described above will be rendered by reference tospecific embodiments that are illustrated in the appended drawings.While it should be understood that these drawings depict only typicalembodiments of the invention and are not therefore to be considered tobe limiting of its scope, the invention will be described and explainedwith additional specificity and detail through the use of theaccompanying drawings, in which:

FIG. 1 is related art illustrating an eye diagram.

FIG. 2 is an image illustrating a classic sample how the time of SingleOne and Single Zero impacts the crossing point.

FIG. 3 is a diagram illustrating a mast of the eye diagram for theupstream transmission signal.

FIG. 4 which is a block diagram illustrating an ONT, according to anembodiment of the present invention.

FIG. 5 is a block diagram illustrating flash memory for ONT, accordingto an embodiment of the present invention.

FIG. 6 is a flow diagram illustrating a process for initializing an ONT,according to an embodiment of the present invention.

FIGS. 7A and 7B are flow diagrams illustrating a process for performingranging, according to an embodiment of the present invention.

FIG. 8 is an illustration of an Upstream_Overhead PLOAM message,according to an embodiment of the present invention.

FIG. 9 is a flow diagram illustrating a process for performing ONUManagement and Control Interface (OMCI) synchronization, according to anembodiment of the present invention.

FIG. 10 is a block diagram illustrating OMCI profiles stored in theflash memory for the ONT, according to an embodiment of the presentinvention.

FIG. 11 is a flow diagram illustrating OMCI configuration recovery perOMCI profiles stored in the flash memory for the ONT, according to anembodiment of the present invention.

FIG. 12 is a flow diagram illustrating a process for performing OMCIsynchronization, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Some embodiments of the present invention pertain to configuring an ONT.See FIG. 4, which is a block diagram illustrating an ONT 400, accordingto an embodiment of the present invention. In some embodiments, ONT 400includes a system on chip (SoC) 402, a laser driver 404, a transceiver406, DDR memory 408, flash memory 410, a subscriber line interfacecircuit (SLIC) 418, and a plurality of RJ45 ports.

During operation, transceiver 406 converts data between electricalsignals and optical signals. For example, transceiver 406 receives andtransmits optical signals to an OLT device (not shown). The opticalsignals are exchanged with remote equipment, such as the OLT device, viaa fiber connected through a fiber connector. The fiber connector may bea standard connector angled physical contact (SC/APC) type or a standardconnector ultra-physical contact SC/UPC type connector.

Transceiver 406 may also transmit and receive electrical signals with alaser driver 404. Laser driver 404 in some embodiments decodes theelectrical signal. For example, when an electrical signal is receivedfrom transceiver 402, laser driver 404 decodes the electronic signal andsends the decoded signal to SoC device 402. Using another example, laserdriver 404 encodes data (or a signal) received from SoC device 402 andsends the encoded signal to control transceiver 406.

Using the encoded signal, laser driver 404 may control transceiver 406by real time micro-managing of transceiver's 406 on and off, itsvoltage, bias current, modulation current, the level of the signals,etc. The purpose of this is to maintain the optical signals, whichtransceiver 406 sends and receives, to meet a certain specification ofthe optical signals. This specification typically defines the range ofan eye diagram of the signals, the range of sending and receiving signalpower level, the extinction radios, the tolerance to reflected power,the sensitivity, and the recovery time, etc. An example of suchspecification may be found in the ITU-T G.984.2 and its amendment.

In order to control transceiver 406, laser driver 404 uses a set ofoptical parameters. See Table 1 below.

TABLE 1 Optical Parameters Parameters Notes TX Laser Select thetransmitting mode: Single Loop, Dual Loop, Mode OpenLoop, etc. RX ModeSelect the receiving mode: APD, STIA APC Auto Power Control for bothtransmitting and receiving ER Set targeted ER TX Power The factors ofthe compensation curve for TX power RX Power The factors of thecompensation curve for RX power Temp The factors of the compensationcurve for Temp Vcc The factors of the compensation curve for DC Voltage(receiving and transmitting) TX impedance Set the transmitting impedanceBias current The factors of the compensation curve for bias current Modcurrent The factors of the compensation curve for modulation current LOSthreshold the threshold of the receiving power of LOS LOS PolarityPolarity of LOS RX Polarity Receiving polarity

It should be appreciated that Table 1 includes a list of opticalparameters. However, this list may vary depending on the embodiment.

This set of the optical parameters includes the initiate value of theregisters of laser driver 404, which are used by its algorithm to drivetransceiver 406 to meet the specifications. The optical parameters alsoinclude other factors used by laser driver's 404 algorithm to compensatethe signals when needed (e.g., when the environmental temperaturechanges). Due to the inconsistency of transceiver 406, the values ofthose optical parameters vary per the type of transceiver 406 beingused.

For this reason, a calibration process is required during themanufacturing of ONT 400. The calibration process may find the mostsuitable set of the parameters to ensure that laser driver 404 driverstransceiver 402 to meet a certain specification of the optical signals,i.e., the specifications under ITU-T G.984.2 and its amendments.

OLT vendors use different optical specifications, or even theirproprietary specifications. For this reason, ONT 400 should also adaptto multiple types of OLT transceivers. To adapt to multiple types of theOLT transceivers, during the manufacture process, ONT 400 is calibratedmultiple times, and in particular, multiple sets of the opticalparameters are stored into flash memory 410. Each set of the opticalparameters provides the information necessary for laser driver 404 todrive transceiver 406 to meet the specifications of the optical signalsand to allow the OLT and ONT 400 to communicate with each other.

FIG. 5 is a block diagram illustrating flash memory 410 for ONT 400,according to an embodiment of the present invention. In someembodiments, flash memory 410 includes a read only area 502 and arewritable area 504. For purposes of configuring the ONT, read only area502 includes multiple sets of optical parameters, each of which includetwo parts of the data—(1) OLT transceiver identifier(s) and (2) ONTtransceiver optical parameters. The OLT transceiver identifier may be apattern that identifies the type of OLT transceiver and may decide ifthe current set of the optical parameters can be used for the OLTtransceiver.

Returning to FIG. 3, when the current set of optical parameters matcheswith the optical parameter read from a message received from the OLT,then the current set of optical parameters is used. Otherwise, SoCdevice 402 checks the next set of optical parameters stored within flashmemory 410. In the event that a match is not found, SoC 402 uses adefault set (e.g., the “Set 5”), which is typically the set of opticalparameters listed under the ITU-T recommendation (ITU-T G.984.2 and itsamendment).

SoC device 402 may also determine and send the set of the opticalparameters to laser drive 404. In response, laser driver 404 initializesitself and drives the transceiver 406 so transceiver 406 can transmitand receive the optical signals. SoC device 402 may also, based on theconfigurations and data received, send another set of optical parametersto laser driver 404 to adapt to a different OLT when needed. This isdescribed in more detail later in this application.

Transceiver Calibration

There are multiple algorithms to calibrate the optical parameters. Forexample, single-loop and dual-loop methods may be used to calibrate theoptical parameters. Some embodiments utilize a different algorithm basedon the OLT transceiver specifications. For example, a dual-loopalgorithm is used for ITU-T standard OLT transceiver (this works formany of the other OLTs). In another example, a single-loop algorithm isused for Arris® OLT transceiver (single loop good for high ER target).

Additionally, there are many parameters that calibrate the ONT duringthe manufacturing process. This calibration may ultimately impact thebehavior of the transceiver. One of the key parameters that help workwith different OLTs is the extinction ratio (ER) as defined below.

$\begin{matrix}{{{ER}({dB})} = {10 \times \log_{10}\frac{{One}\mspace{11mu}{level}}{{Zero}\mspace{14mu}{level}}}} & {{Equation}\mspace{14mu}(2)}\end{matrix}$

The ER measurement may apply to optical signals, and may be defined as aratio of power level of One level and/or Zero level. By increasing theER, the signal can be recognized, but may require a higher overall powerassumption. It should be noted that the ER may or may not impact thecrossing point. Further, the ER is calibrated to 14 dB for Type S OLTtransceivers and Type B OLT transceivers, and the ER is calibrated to 18dB for Type A OLT transceivers.

ONT Initialization Process

The typical ONT initialization process covers the ONT hardware andfirmware initialization, and ends when ONT is ready to receive opticalsignals. However, for purposes of explanation, the initializationprocess can be extended to or until the ONT is connected to the OLT andis ready to receive OMCI configuration from the OLT.

Returning to FIG. 5, the ONT may store the configurations in rewritablearea 504 of flash memory 410. Those configurations include, but are notlimited to, an index of the optical parameters set currently being used,the current OMCI profile, the latest OMCI configurations from the OLT,the local configuration files, and application/service configuration, toname a few. Such configurations are stored in rewritable area 504 as itmay be changed anytime when the ONT is running. Further, theseconfigurations are stored in flash memory 410 so that, when the ONTreboots, the ONT can retrieve the stored last successful configurationto recover the services much more quickly. For example, in most of thecases, the ONT may still connect to the same OLT and, by using thestored “currently used optical parameters”, may not have to try andre-initiate the laser driver with different optical parameter sets(optical parameters will match at the first try). This configuration mayalways be removed from flash memory 410 without any issue. The ONT mayfollow the same process to initiate the components and get configuredbased on the messages from the OLT.

Some of these configurations are defined in the ITU-T recommendationssuch as ITU-T G.984.3, G.984.4 and G.988. Other configurations may bevendor specific. However, the sets of the optical parameters are storedin read only area 502 of flash memory 410 as such parameters cannot bechanged except in the calibration process during the manufacture.Further, potential change to some of the optical parameters may causeproblems and may result in the permanent failure to connect to sometypes of the OLTs.

It should be noted, however, that the parameters the OLT sends throughthe PLOAM message are not stored in FLASH. Instead, those parameters arestored in DDR memory 408 (or any similar device in which the data willbe lost when power off or restarts, such SRAM, DRAM, etc.) of FIG. 4.Such parameters include preambles, delimiters, power level adjustment,ranging time, advanced encryption standard (AES) keys, etc.

The rewritable area 504 of flash memory 410 may, in some embodiments,include manufacture information, such as serial number, MAC address,identifier of the optical parameter set (e.g., default “Set S”), OMCIconfigurations, and other service configuration files. Such manufactureinformation are changeable, even though for diagnostics purpose only.Further, such a change would not create a problem for the ONT itself(except OLT may identify it as another one).

FIG. 6 is a flow diagram illustrating a process 600 for initializing anONT, according to an embodiment of the present invention. In someembodiments, process 600 may begin at 602 with powering on the ONT. At604, the configuration from the rewritable area of flash memory isloaded. Note, in embodiments where the ONT is powered on for the firsttime, or the in embodiments where ONT is reset to a factory defaultstatus, the ONT may not have some of the configuration (e.g., OMCIconfiguration) preloaded. In those embodiments, ONT uses the defaultOMCI profile to generate an initialized OMCI configuration, which has noservice configured. A default “current OLT transceiver type” is setduring manufacturing, which typically point to the set of opticalparameters recommended by the ITU-T Recommendation. In otherembodiments, the set of optical parameters may be the first set of theoptical parameters stored in the read only area of the flash memory.

At 606, after the ONT restores the configurations from the flash memory,the ONT distributes the data to related parts. For example, the opticalparameters are sent to laser driver so the laser driver can use thoseoptical parameters to control the transceiver, and later on, compensatethe signals based on the laser's driver's internal logic. After applyingthe restored configuration and data, the transceiver is ready to connectto OLT. At 608, the transceiver is activated to receive data from theOLT, which starts the ranging process (i.e., a handshake mechanismdefined in the ITU-T G.984.3).

FIGS. 7A and 7B are flow diagrams illustrating a process 700 forperforming ranging (i.e., the handshake process between the ONT and theOLT), according to an embodiment of the present invention. In someembodiments, process 700 may begin at 702 with the ONT (i.e., thetransceiver) receiving a PLOAM message (e.g., an Upstream_Overhead PLOAMmessage defined by Section 9.2.3.1 of the ITU-T G.984.3). The PLOAMmessage may include parameters instructing how the ONT (e.g.,transceiver) should send the optical signals so the OLT (e.g., OLT'stransceiver or receiver) can recognize those optical signals. Theseparameters may include preamble bytes, the delimiter bytes, the ONUpower level mode, and the pre-assigned delay, to name a few.

TABLE 1 Upstream_Overhead PLOAM Message Upstream_Overhead message OctetContent Description  1 11111111 Broadcast message to all ONUs.  200000001 Message identification ″Upstream_Overhead″.  3 gggggggggggggggg = Number of guard bits.  4 xxxxxxxxxxxxxxxx = Number of type 1 preamble bits. Type 1 preamble bitscontain the ′all-ones′ pattern. This may be set to zero.  5 yyyyyyyyyyyyyyyy = Number of type 2 preamble bits. Type 2 preamble bitscontain the ′all-zeroes′ pattern. This may be set to zero.  6 cccccccccccccccc = Pattern to be used for type 3 preamble bits (Note 1).  7bbbbbbbb Data to be programmed in delimiter byte 1 (Notes 2 and 3).  8bbbbbbbb Data to be programmed in delimiter byte 2.  9 bbbbbbbbData to be programmed in delimiter byte 3. 10 xxemsspp xx = Reserved:e = Status of delay pre-equalization mechanism: ″0″ = Nopre-assigned delay, ″1″ = Use pre-assigned delay given below.m = Status of SN_Mask mechanism: ″0″ = SN_Mask disabled,″1″ = SN_Mask enabled (Note 5).ss = Max number of extra SN-transmissions sent in response to asingle SN-request. For example, ss = 10 means an ONU will send 3SN-transmissions when responding to a SN-request (Note 6).Default ONU transmit power level mode: pp = ″00″-Mode 0: Normal.pp = ″01″-Mode 1: Normal-3 dB. pp = ″10″-Mode 2: Normal-6 dB.pp = ″11″-Reserved. (Note 4) 11 ddddddddMSB of pre-assigned delay (32 byte units). 12 ddddddddLSB of pre-assigned delay (32 byte units). NOTE 1-The length of Type 3preamble can be calculated by subtracting the number of bits allocatedto guard time, type 1 preamble and type 2 preamble, by theUpstream_Overhead message, as well as 24 bits of the delimiter from thetotal burst mode overhead time specified in Table 1.2 of [ITU-T G.984.2]The ONU uses the octet 6 pattern to fill the length of type 3 preamble,aligning the MSB of the pattern with the MSB of the preamble, repeatingthe pattern as many time as necessary, and leaving any partial patternadjacent to the delimiter. NOTE 2-The delimiter pattern occupies thelast 24 bits of the burst mode overhead time. In those cases when theactual delimiter is shorter than 24 bits, it is the responsibility ofthe OLT to specify the pattern in octet 7 so that its MSB can serve asthe latter part of the preamble. NOTE 3-For 16-bit delimiters, thesevalues are proposed: 0x85B3, 0x8C5B, 0xB433, 0xB670 and 0xE6D0. For20-bit delimiter, 0xB5983 is proposed. NOTE 4-Be mindful that the codingof the power level modes in the upstream overhead message, where 0 ishighest and 2 is lowest, is opposite to that in the Serial_Number_ONUmessage. NOTE 5-As the Serial_Number_Mask message has been deprecated,the m bit shall be set to 0. NOTE 6-As multiple SN transmission methodhas been effectively deprecated, ss bits shall be set to 00.

FIG. 8 is an illustration of an Upstream_Overhead PLOAM message (orPLOAM message) 800, according to an embodiment of the present invention.In PLOAM message 800, the pattern of Byte 10 identifies the type of theOLT transceivers. For example, a transceiver made by Fiberxon®, which istypically used by Arris®, has identifier 0x22. The transceivers, whichare used by ALU® OLTs and Calix® OLTs, have identifier 0x00. Thetransceiver, which is used by Adtran® OLT, has identifier 0x20.

Returning back to FIG. 7A, the ONT (e.g., the laser driver) extractsByte 10 data from the PLOAM message at 704. At 706, the ONT (e.g., theSoC) compares the Byte 10 data with the identifier(s) of each set ofoptical parameters stored in the rewriteable area of the flash memory.See FIG. 5. For example, the ONT selects the first set of opticalparameters stored in the rewritable area of the flash memory, and thefirst set is then compared with the Byte 10 data.

At 708, the ONT (i.e., the SoC) determine if the Byte 10 data matcheswith one of the identifier(s) in the selected first set of opticalparameters. If a match is not found, then at 710 the ONT selects (orloads) another set of optical parameters stored in the read only area ofthe flash memory and compares the selected other set of opticalparameters with the Byte 10 data. Note, this process may continue untila match is found.

If, however, a match is found, then at 712, the ONT stores the Byte 10data in the DDR memory and waits for a serial number (SN) request fromthe OLT. The SN request message is a special BWmap entry defined inSection 10.2.5.2 of ITU-T G.984.3. It should be appreciated that theBWmap, sending in downstream from OLT to ONT, is typically used for theOLT to allocate the time slot of the ONT transmission in an upstreamdirection (e.g., sending data from the ONT to the OLT). However, whenthe BWmap is used as SN request message, the BWmap may be defined assuch, not only grant an exact time slot for the ONT to send theSerial_Number_ONU PLOAM message, but also indicate that only theSerial_Number_ONU PLOAM message can be sent. All ONTs, which are waitingfor the SN request message, can send the Serial_Number_ONU PLOAM messageat this stage. Those already are assigned ONU-ID are not be allowed tosend Serial_Number_ONU PLOAM message. Those are not yet ready to receiveSN request (i.e., those that have not yet receive Upstream_OverheadPLOAM message) are not be allowed to send Serial_Number_ONU PLOAMmessage. At 714, upon receipt of the SN request from the OLT, the ONT(i.e., the transceiver) sends the SN via a Serial_Number_ONU PLOAMmessage. In some embodiments, the Serial_Number_ONU PLOAM message isdefined in Section 9.2.4.1 of ITU-T G.984.3).

At 716, the ONT receives an Assign_ONU-ID PLOAM message from the OLT.The Assign_ONU-ID PLOAM message may be defined in Section 9.2.3.3 ofITU-G.984.3. At 718, if ONT does not receive Assign_ONU-ID PLOAM messagewithin a predefined time period (e.g., 10 seconds in some embodiments),the ONT aborts the activation attempt and waits for SN request againbefore sending the SN via a Serial_Number_ONU PLOAM message one moretime. In this case, the ONT checks at 720 if all sets of opticalparameters have been tried, and if all sets have been tried, thenprocess 700 returns to step 702. In an alternative embodiment, ONT maywait for SN request from the OLT and try one more time with a new set ofoptical parameters. In such an embodiment, when all sets of parametersare tried, the process may then return to step 702. This alternativeembodiment does not impact the OLT's behavior as defined in ITU-TSpecification.

Otherwise, process 700 continues to step 722 with the ONT loading thenext available set of optical parameters. At 724, when the ONT fails toreceive the Assign_ONU-ID PLOAM message from the OLT within a predefinedtime period, process 700 returns to step 712.

If, however, the ONT receives the Assign_ONU-ID PLOAM message within thepredefined time period, then at 726, the ONT completes the rangingprocess with the OLT. When the ONT receives the Assign_ONU-ID PLOAMmessage, the ONT may expect another special BWmap entry—ranging request.The ranging request, similar to SN request but for a particular ONU-ID,grants an exact time slot for that particular ONT to sendSerial_Number_ONU PLOAM message one more time. This may allow the OLT,based on the response time, to calculate the distance between the OLTand ONT and compensate the transmission delay caused due to thedistances. Such compensation may be set to the ONT by the Ranging TimePLOAM message. ONT completes the ranging process when receives theRanging Time PLOAM message from OLT. This process may be defined inITU-T G.984.3. Upon completion of the ranging process, the ONT may beginthe OMCI synchronization process.

OMCI Synchronization

Even though the same OLT transceiver is used, the OMCI profile may bedifferent depending on the vendor. To automatically adapt differentOLTs, ONT may also detect the OLT's OMCI profile and switchautomatically. FIG. 9 is a flow diagram illustrating a process 900 forperforming OMCI synchronization, according to an embodiment of thepresent invention.

In some embodiments, process 900 may begin at 902 with the ONT startingthe OMCI interaction with the OLT. For example, the ONT receives theOLT-G OMCI message from the OLT. The OLT-G OMCI message may includeOLT's vendor ID, equipment ID, version, etc.

9.12.2 OLT-G

This optional ME (Managed Entity, this is a term in ITU-T G.988)identifies the OLT to which an ONU is connected. This M E provides a wayfor the ONU to configure itself for operability with a particular OLT.It also provides a way for the OLT to communicate the time of day to theONU.

An ONU that supports this ME automatically creates an instance of it.Immediately following the start-up phase, the OLT should set the ONU tothe desired configuration. Interpretation of the OLT vendor ID,equipment ID and version attributes is a matter for negotiation betweenthe two vendors involved.

Relationships

The single instance of this ME is associated with the ONU ME.

Attributes

Managed entity ID: This attribute uniquely identifies each instance ofthis ME. There is only one instance, number 0. (R) (mandatory) (2 bytes)

OLT vendor ID: This attribute identifies the OLT vendor. It is the sameas the four most significant bytes of an ONU serial number specified inthe respective TC layer specification. Upon instantiation, thisattribute comprises all spaces. (R, W) (mandatory) (4 bytes)

Equipment ID: This attribute may be used to identify the specific typeof OLT. The default value of all spaces indicates that equipment IDinformation is not available or applicable to the OLT being represented.(R, W) (mandatory) (20 bytes)

Version: This attribute identifies the version of the OLT as defined bythe vendor. The default left-justified ASCII string “0” (padded withtrailing nulls) indicates that version information is not available orapplicable to the OLT being represented. (R, W) (mandatory) (14 bytes)

Time of day information: This attribute provides the informationrequired to achieve time of day synchronization between a referenceclock at the OLT and a local clock at the ONU. This attribute comprisestwo fields: the first field (4 bytes) is the sequence number of thespecified GEM superframe. The second field (10 bytes) is TstampN asdefined in clause 10.4.6 of [ITU-T G.984.3], clause 13.2 of [ITU-TG.987.3] and clause 13.2 of [ITU-T G.989.3], using the timestamp formatof clause 5.3.3 of [IEEE 1588]. The value 0 in all bytes is reserved asa null value. (R, W) (optional) (14 bytes)

NOTE—In ITU-T G.987/ITU-T G.989 systems, the superframe count field ofthe time of day information attribute contains the 32 LSBs of the actualcounter.

Actions

Get, set

Notifications

None.

At 904, the ONT determines if the OMCI message contained the OLT-Gentity identifying the OLT's vendor. In some embodiments, the OLT-G isconsidered as the OLT vendor identification (ID). If the OMCI messagedoes not contain the OLT-G entity, process 900 may then return back tostep 902 with the ONT waiting for receipt of a new OMCI message from theOLT.

If the OMCI message contained the OLT-G entity, the ONT determines ifthe OLT vendor ID matches with the current vendor ID at 906. The currentvendor ID may be stored in the rewritable area of flash memory as a partof the local copy of OMCI configuration. If the OLT vendor ID matcheswith the current vendor ID, then at 908, the ONT selects a OMCI handlerbased on the version identified in the OLT-G entity and return to step904 waiting for another OMCI message.

At 910, if the OLT vendor ID does not match with the current vendor ID,then the ONT sets (or updates) the current OLT vendor as the new vendorID and stores the new vendor ID in rewritable area of flash memory.

At 912, after updating the new vendor ID, the ONT deletes the OMCIconfiguration stored in the flash memory (except the current OLT vendorwhich was updated in previous step). At 914, the ONT is then rebooted,allowing the ONT to initialize the OMCI configuration using the new OMCIprofile.

In some embodiments, the ONT checks the version of OLT via Attribute“Version (14 bytes)” of OLT-G entity to decide the correct parsingprocedure and function for OLT configuration. This may be implemented byselecting different callbacks base on OLT-G Version Attribute, whichdoes not require a reboot. In these embodiments, the checking may takeplace at 908. As defined in OLT-G entity, the vendor ID and the versionare both configurable. When the ONT receives an OLT-G message, eventhough the vendor ID remains the same, ONT may still check the versioninfo to see if the OMCI handler/callbacks shall be changed. It oftenhappens when the OLT is upgraded to a new version, which request adifferent implementation for some certain configurations at the ONT.

Also, in some embodiments, process 900 does not connect to the previousoptical parameters since the OLT transceiver it typically pluggable. Theoptical parameters are determined by the transceiver type and not OLTvendor. Note, however, the OMCI profile is determined by the OLT vendorsas the OMCI profile relies on the firmware of OLT system.

FIG. 10 is a block diagram illustrating OMCI profiles stored in theflash memory 1000 for the ONT, according to an embodiment of the presentinvention. As discussed, flash memory 1000 includes read only area 1002and rewritable area 1004. Within rewriteable area 1004 includes OMCIprofile 1006 includes a set of data used to initialize OMCIconfiguration, and a set of APIs used to react to some certain OMCIconfigurations for a particular OLT. The standard OMCI profile isdefined by ITU-T G.988 recommendation and its amendments. However, manyOLT vendors extend or modify the definition of the “standard”recommendation in the implementation. Such modifications may also changefrom one OLT release to another. The data that used to initialize OMCIconfiguration includes the default value of the OMCI entities defined inthe ITU-T recommendation as well as those vendor specific entityextensions, and also the vendor specific value such as the slot ID,equipment information, etc. The APIs are used to react or behaveaccording to the OMCI configurations which, even for the sameconfiguration, the ONT's behaviors may be different from one OLT toanother or from one OLT version to another. For example, the same VLANclassification configuration may result to different VLAN classificationbehavior depending on the OLT vendor ID and OLT version.

Due to the facts that many of OLT vendors expects different initial OMCIconfigurations and behavior to an OMCI configuration, the vendorspecific OMCI profiles are defined and included in ONT firmware andidentified such profiles based on the vendor ID and also (optional) OLTversion. Such profiles are hardcoded in the ONT firmware which stored inthe flash memory of the ONT.

It should be appreciated that during the manufacture process, a defaultvendor ID and OLT version can be preset in the manufacture data.

When the ONT boots up (see FIG. 6, step 604), ONT detects if an OMCIconfiguration exists from previous operation. If ONT operated beforewith an OLT, the OMCI configuration is stored in the flash memory. Thismay not be the case in embodiments where a reset to factory default ismade. If the configuration exists, the ONT restores the OMCIconfiguration from flash memory before trying to sync up with OLT. Thishelps ONT recover the last successful configuration quickly. Dependingon the OLT's implementation, the recovery time may be reduced by 10 to30 seconds. If the configuration does not exist, ONT initializes theOMCI configuration and API based on the preset vendor ID and OLTversion. If there is no preset vendor ID, the standard OMCI profile isused.

Following figure describes the details associated with step 604 of FIG.6, i.e., how the OMCI configuration is restored or initialized based onthe different OMCI profiles. FIG. 11 is a flow diagram illustrating aprocess 1100 for OMCI configuration recovery per OMCI profiles,according to an embodiment of the present invention. Process 1100 maybegin at 1102 with determining if the OMCI configuration is previouslystored in the flash memory. If the OMCI configuration is stored therein,the OMCI configuration is loaded from the flash memory at 1104,completing the loading process. If, however, the OMCI configuration isnot stored in flash memory, then at 1106, the OLT determines if thevendor ID and the OLT version will be configured. In some embodiments,OLT sets the OLT-G ME Value. When the vendor ID and OLT version isconfigured, then at 1108, the OMCI configuration is initialized, therebycompleting the loading process. For example, the OMCI profile perconfigured vendor ID and OLT version is used to initialize the OMCIconfiguration.

Otherwise, at 1110, the ONT determines if the vendor ID is preset duringthe manufacturing process. If so, at 1112, the OMCI profile per presetvendor ID and OLT version is used to initialize the OMCI configuration,thereby completing the loading process. If, however, the ONT determinesthat the vendor ID is not preset, the standard OMCI profile is used at1114 to initialize the OMCI configuration, thereby completing theloading process. In some embodiments, If the OLT has not configuredOLT-G, ONT uses pre-set value during the manufacturing process.

In some embodiments, when the ONT is started, the OMCI configuration issynchronized with the OLT and the ONT receives an OMCI messagecontaining an OLT-G entity identifying a vendor of OLT and also the OLTversion. In these embodiments, the ONT determines if the OLT vendor IDmatches with the currently used vendor ID and determines if the OLTversion is compatible with the OMCI profile it currently uses. If theOLT vendor ID fails to match or the OLT version is not compatible withthe OMCI profile, ONT updates the OLT vendor ID, deletes the previouslystored OMCI configuration from flash memory, and selects a new OMCIprofile. The ONT is then rebooted, allowing the ONT to initialize theOMCI configuration using this new OMCI profile.

FIG. 12 is a flow diagram illustrating a process 1200 for performingOMCI synchronization, according to an embodiment of the presentinvention. In some embodiments, process 1200 may begin with starting theOMCI interaction by receiving OLT OMCI messages at 1202. At 1204, theONT determines if OLT-G information is received from OLT. If not, theONT responds with the next OLT and receives the next OMCI message at1206, and returns to step 1204.

If the OLT-G information is received from the OLT, then at 1208, the ONTdetermines if the OLT vendor matches current vendor ID, and if the OLTversion is compatible with current OMCI handlers. If there is a match,the OMCI handler is selected based on a version of the OLT-G at 1210. Ifa match does not exist, then the current OLT vendor is set to equal tonew vendor ID at 1212, and the OMCI configuration is deleted from theflash memory at 1214. At 1216, the ONT is then rebooted, allowing theONT to initialize the OMCI configuration using this new OMCI profile.

It will be readily understood that the components of various embodimentsof the present invention, as generally described and illustrated in thefigures herein, may be arranged and designed in a wide variety ofdifferent configurations. Thus, the detailed description of theembodiments of the present invention, as represented in the attachedfigures, is not intended to limit the scope of the invention as claimed,but is merely representative of selected embodiments of the invention.

The features, structures, or characteristics of the invention describedthroughout this specification may be combined in any suitable manner inone or more embodiments. For example, reference throughout thisspecification to “certain embodiments,” “some embodiments,” or similarlanguage means that a particular feature, structure, or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, appearances of the phrases“in certain embodiments,” “in some embodiment,” “in other embodiments,”or similar language throughout this specification do not necessarily allrefer to the same group of embodiments and the described features,structures, or characteristics may be combined in any suitable manner inone or more embodiments.

It should be noted that reference throughout this specification tofeatures, advantages, or similar language does not imply that all of thefeatures and advantages that may be realized with the present inventionshould be or are in any single embodiment of the invention. Rather,language referring to the features and advantages is understood to meanthat a specific feature, advantage, or characteristic described inconnection with an embodiment is included in at least one embodiment ofthe present invention. Thus, discussion of the features and advantages,and similar language, throughout this specification may, but do notnecessarily, refer to the same embodiment.

Furthermore, the described features, advantages, and characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. One skilled in the relevant art will recognize that theinvention can be practiced without one or more of the specific featuresor advantages of a particular embodiment. In other instances, additionalfeatures and advantages may be recognized in certain embodiments thatmay not be present in all embodiments of the invention.

One having ordinary skill in the art will readily understand that theinvention as discussed above may be practiced with steps in a differentorder, and/or with hardware elements in configurations which aredifferent than those which are disclosed. Therefore, although theinvention has been described based upon these preferred embodiments, itwould be apparent to those of skill in the art that certainmodifications, variations, and alternative constructions would beapparent, while remaining within the spirit and scope of the invention.In order to determine the metes and bounds of the invention, therefore,reference should be made to the appended claims.

1. A method for performing ONU Management and Control Interface (OMCI)synchronization, the method comprising: receiving an OMCI messagecontaining a OLT-G entity identifying OLT's vendor identification (ID)and version; determining if an OLT vendor identification (ID) matcheswith a current vendor ID and if an Optical Line Terminal (OLT) versionis compatible with current OMCI handlers; when the OLT vendor ID failsto match with the current vendor ID, automatically performing a OMCIhandler switching process, wherein the OMCI handler switching processcomprises setting a current OLT vendor as a new OLT vendor ID; aftersetting the new OLT vendor ID, deleting a OMCI configuration previouslystored in the flash memory; and rebooting the ONT, allowing the ONT toinitialize a OMCI configuration using a new OMCI profile.
 2. The methodof claim 1, further comprising: determining if the OMCI configuration ispreviously stored in the flash memory; and when the OMCI configurationis stored in the flash memory, loading the OMCI configuration is loadedfrom the flash memory, completing an OMCI loading process.
 3. The methodof claim 2, further comprising: when the OMCI configuration is notstored in the flash memory, determining, by the OLT, if the vendor IDand the OLT version will be configured; and when the vendor ID and OLTversion is configured, initializing the OMCI configuration, therebycompleting the OMCI loading process, wherein the initializing of theOMCI configuration comprises using the OMCI profile per configuredvendor ID and OLT version to initialize the OMCI configuration.
 4. Themethod of claim 3, further comprising: determining, by the ONT, if thevendor ID is preset during the manufacturing process; and when thevendor ID is preset, using the OMCI profile per preset vendor ID and OLTversion to initialize the OMCI configuration, thereby completing theloading process.
 5. The method of claim 4, further comprising: when theONT determines that the vendor ID is not preset, using a standard OMCIprofile to initialize the OMCI configuration, thereby completing theloading process.
 6. The method of claim 4, further comprising: when ONTdetermines that the OLT has not configured OLT-G, using, by the ONT, apre-set value during the manufacturing process.
 7. A system configuredto perform ONU Management and Control Interface (OMCI) synchronization,the system comprising: an optical network termination (ONT) configuredto receive an OMCI message containing a OLT-G entity identifying OLT'svendor identification (ID) and version, and determine if an OLT vendoridentification (ID) matches with a current vendor ID and if an OpticalLine Terminal (OLT) version is compatible with current OMCI handlers,wherein when the OLT vendor ID fails to match with the current vendorID, automatically perform a OMCI handler switching process, wherein theOMCI handler switching comprises setting a current OLT vendor as a newOLT vendor ID; after setting the new OLT vendor ID, deleting a OMCIconfiguration previously stored in the flash memory; and rebooting theONT, allowing the ONT to initialize a OMCI configuration using a newOMCI profile.
 8. The system of claim 7, wherein the ONT is furtherconfigured to determine if the OMCI configuration is previously storedin the flash memory, and when the OMCI configuration is stored in theflash memory, load the OMCI configuration from the flash memory,completing an OMCI loading process.
 9. The system of claim 8, whereinthe OLT is configured to when the OMCI configuration is not stored inthe flash memory, determine if the vendor ID and the OLT version is tobe configured, and when the vendor ID and OLT version is to beconfigured, initialize the OMCI configuration, thereby completing theOMCI loading process, wherein the initializing of the OMCI configurationcomprises using the OMCI profile per configured vendor ID and OLTversion to initialize the OMCI configuration.
 10. The system of claim 9,wherein the ONT is further configured to determine if the vendor ID ispreset during the manufacturing process, and use the OMCI profile perpreset vendor ID and OLT version to initialize the OMCI configuration,thereby completing the loading process, when the vendor ID is preset.11. The method of claim 10, wherein the ONT is configured to use astandard OMCI profile to initialize the OMCI configuration, therebycompleting the loading process, when the vendor ID is not preset. 12.The system of claim 10, wherein the ONT is further configured to use apre-set value during the manufacturing process, when the OLT has notconfigured OLT-G.